tar: fix --to-command wrt short writes

function                                             old     new   delta
bb_copyfd_exact_size                                  51      98     +47
bb_full_fd_action                                    362     394     +32
get_header_tar                                      1546    1558     +12
data_extract_to_command                              430     439      +9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 100/0)             Total: 100 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/archival/libunarchive/data_extract_to_command.c b/archival/libunarchive/data_extract_to_command.c
index 983c5301d0e57ed3c1b76d9235e3e49671058e28..53a7217c2580f5d12949721e75a92e3c400be1be 100644 (file)
--- a/archival/libunarchive/data_extract_to_command.c
+++ b/archival/libunarchive/data_extract_to_command.c
@@ -108,7 +108,7 @@ void FAST_FUNC data_extract_to_command(archive_handle_t *archive_handle)
                close(p[0]);
                /* Our caller is expected to do signal(SIGPIPE, SIG_IGN)
                 * so that we don't die if child don't read all the input: */
-               bb_copyfd_exact_size(archive_handle->src_fd, p[1], file_header->size);
+               bb_copyfd_exact_size(archive_handle->src_fd, p[1], -file_header->size);
                close(p[1]);
 
                if (safe_waitpid(pid, &status, 0) == -1)

diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index f42eb76239890085f7f15cb086967872fcf677dc..2538d496dbcf63ec707db0db2da8f7a18bf6b5f3 100644 (file)
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -9,8 +9,10 @@
 
 #include "libbb.h"
 
-/* Used by NOFORK applets (e.g. cat) - must not use xmalloc */
-
+/* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
+ * size < 0 means "ignore write errors", used by tar --to-command
+ * size = 0 means "copy till EOF"
+ */
 static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 {
        int status = -1;
@@ -21,6 +23,12 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 #else
        char *buffer;
        int buffer_size;
+       bool continue_on_write_error = 0;
+
+       if (size < 0) {
+               size = -size;
+               continue_on_write_error = 1;
+       }
 
        if (size > 0 && size <= 4 * 1024)
                goto use_small_buf;
@@ -63,8 +71,11 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
                if (dst_fd >= 0) {
                        ssize_t wr = full_write(dst_fd, buffer, rd);
                        if (wr < rd) {
-                               bb_perror_msg(bb_msg_write_error);
-                               break;
+                               if (!continue_on_write_error) {
+                                       bb_perror_msg(bb_msg_write_error);
+                                       break;
+                               }
+                               dst_fd = -1;
                        }
                }
                total += rd;
@@ -108,7 +119,7 @@ off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size)
 void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size)
 {
        off_t sz = bb_copyfd_size(fd1, fd2, size);
-       if (sz == size)
+       if (sz == (size >= 0 ? size : -size))
                return;
        if (sz != -1)
                bb_error_msg_and_die("short read");